In other words, to quote an excellent article on Bloodhorse by Craig I read a few years ago:
"The Belmont Stakes is a unique race, 12 furlongs on dirt, and as such it should not be surprising that traditional handicapping methods do not work very well. The most solid conclusion that can be drawn is that the pace will be average-to-fast; it has been slow only once in the last 11 runnings of the race. Pace analysis generally favors speed horses when the pace is slow and off-pace runners when the pace is fast. But those rules do not appear to apply to the Belmont. Likewise, speed figures earned in races at distances spanning nine to 10 furlongs rarely indicate what a horse can run at 12 furlongs, just as a six furlong speed figure doesn’t mean all that much at a mile"
Perfect!
Only thing I would have liked added to this advice is, while saying traditional handicapping methods do not work very well, he did not offer an opinion of what (if any) other methods do work.
It's probably in an article I missed somewhere.
What else I thought was interesting, as an aside, was an article by Andy Beyer who said: "Beyer Speed Figures, which measure how fast a horse has run in each of his races, provide a graphic example of American racehorses’ unsuitability to the 1½-mile distance of the Belmont Stakes."
Basically, he is saying his figures for 1-1/2 are suitable but the American racehorse isn't.